KINSHASA, Congo -- Soldiers backed by U.N. helicopter gunships battled rebels around a strategic army garrison near a mountain gorilla reserve in eastern Congo, as thousands of people continued to flee a 3-month-old rebellion allegedly backed by neighbouring Rwanda.

U.N. Radio Okapi said the rebels Thursday began attacking Rumangabo military camp, which the soldiers had only retaken from the M23 rebel group on Wednesday. The camp is a mile (kilometre) from the headquarters of the Virunga National Park, whose rangers were forced to flee by fighting earlier this month.

The radio station said the rebels continue to hold Rutshuru town and nearby Kiwanja, and that thousands of people had fled in recent days. More than 260,000 civilians have been forced from their homes in recent months, according to U.N. agencies, some across the borders to Uganda and Rwanda, others toward the southern provincial capital of Goma.

Maj. Olivier Hamuli, an army spokesman, said soldiers made a strategic retreat from Rutshuru "to avoid a bloodbath" of civilians.

"Actually the operations at the front are running well," he said by telephone late Wednesday. Hamuli said soldiers had retaken several other villages by Wednesday evening, including Bukima, which he described as a rebel training centre for young recruits.

U.N. spokesmen this week explained the use of helicopter gunships by the U.N. mission, called MONUSCO, to support Congolese troops fighting the rebels.

At the United Nations, Eduardo del Buey, deputy spokesman for the U.N. secretary-general, on Wednesday described how "MONUSCO and the FARDC launched an immediate counteroffensive, also including firing, using (U.N.) Mission attack helicopters ..." when rebels attacked a Congolese army base on Tuesday.

In Kinshasa, Congo's capital, a spokesman for the U.N. military mission said the helicopters are used first as a projection of force. Spokesman Commandant Thibaut De Lacoste said the helicopters generally make two passes before resorting to live fire.

First, a helicopter makes a low-level flight, buzzing to alert those below that they have been sighted and are under surveillance, De Lacoste told a news briefing on Wednesday.

Secondly, a helicopter will fire rocket flares, illuminating the area and warning "We have not only seen you but we are capable of opening fire."

On the third pass, the U.N. peacekeepers can resort to using live munitions, he said, "warning of the potential results of our fire if you cross the red line."

On Tuesday, the rebels came within 25 kilometres (16 miles) of Goma, battling soldiers at Kibumba and forcing into flight the thousands of people who have made Kibumba a centre for refugees from a 2009 rebellion.

The rebels are accused of numerous human rights abuses including rape and forcefully recruiting children into their ranks. Soldiers also are accused of rape and widespread looting.

Rwanda, which vigorously denies having anything to do with the rebels, this week accused Congolese troops of ill-treating Rwandan nationals and charged one of four detained at an army camp was tortured to death.

"This is an extremely serious incident - we have confirmation that one of the tortured Rwandans has died," Rwandan Foreign Minister Louise Mushikiwabo said in a statement posted Thursday on her ministry Web site. "We have asked the government of the DRC (Congo) to ensure that the mistreatment of Rwandan citizens stops immediately."

Many Rwandans have been abused and some attacked since a U.N. report last month said it provided overwhelming evidence that Rwanda's military helped create, arm and support the M23 rebel group, including by sending Rwandan troops to fight alongside them against Congo's army. The insurgents are members of an earlier Rwandan-backed rebellion who were integrated into the Congolese army in 2010 and began deserting in April, demanding better implementation of a peace pact.

The United States last week announced it was cutting $200,000 in military aid to Rwanda to show it is "deeply concerned about the evidence" implicating Rwanda. The amount involved is small compared to all U.S. aid to Rwanda, but it was seen as a very public rebuke from a usually staunch ally.

Photos

A United Nations helicopter circles overhead as U.N. peacekeepers from Uruguay patrol in a show of force to reassure the local population, in Goma, eastern Congo July 13, 2012. (AP Photo/Marc Hofer)